# What are the products in the following reaction: ?Na_3PO_4(aq) + ?CaCl_2(aq) -> ?NaCl(aq) + ?Ca_3(PO_4)_2(s)?

Jan 7, 2017

$\text{Calcium phosphate}$ and $\text{sodium chloride}$. Of course there is speciation of the phosphate ion in aqueous solution.

#### Explanation:

Most phosphates are in fact biphosphates, i.e. salts of ["HPO"_4]""^(2-); this is certainly true in aqueous solution, where phosphate ion, ["PO"_4]""^(3-), is a powerful Bronsted base:

$\text{PO"_4""^(3-) + "H"_2"O" rarr "HPO"_4""^(2-) + ""^(-)"OH}$

In solution, your equation probably represents the reaction:

$\text{Na"_2"HPO"_4(aq) + "CaCl"_2(aq) rarr "CaHPO"_4(s)darr+2"NaCl} \left(a q\right)$.

If we keep with the equation as written, we get:

$\text{Na"_3"PO"_4(aq) + "3CaCl"_2(aq) rarr "Ca"_3("PO"_4)_2(s)darr+2"NaCl} \left(a q\right)$.

Which I think is balanced with respect to mass and charge. I do not think that the 2nd reaction reflects chemical reality.